Patent GB-387723-A (GB)
Title: Improvements in electrical power systems comprising storage batteries
IPC: H02J7/34
Filed: 1931-08-13
Abstract: 387,723. Charging and discharging batteries. ELECTRICAL RESEARCH PRODUCTS, Inc., 195, Broadway, New York, U.S.A.-(Assignees of Holden, W. H. T. ; 57, Lincoln Road, Brooklyn, Jutson, R. P. ; 38, Park Avenue, Yonkers, both in New York, and Larew, J. L., Upper Main Street, South Amboy, New Jersey, both in U.S.A.) Aug. 13, 1931, No. 22925. Convention date, Aug. 13, 1930. [Class 38 (iv).] Regulation, automatic.-In a system in which a battery, constantly connected to a load circuit, is charged from a source of rectified current, the charging current is controlled by means responsive to the load circuit voltage which maintains that voltage within prescribed limits, and, on failure of the source, controls apparatus constantly compensating for the resulting fall in battery voltage, and the gradual rise which ensues when the source is restored, until the battery is fully charged. Extra cells are added to the battery during the abnormal period, and the compensating apparatus comprises counter e.m.f. cells in association with an impedance varied by a reversibly controlled motor. While the charging source is operative the voltage responsive means cuts in and out of circuit a fixed or manually adjustable impedance, but on a failure it controls the impedance associated with the annular e.m.f. cells. When the source is restored the rate of charging is increased by connecting additional rectifiers into circuit, and the normal control is restored by the action of an ampere-hour meter when the battery becomes fully charged. The normal charging circuit includes two singlephase rectifiers 4, 5 with their outputs in series with an adjustable resistance 22, battery sections 11, 12 in parallel and the contacts of an end-cell switch 31. The load circuit 9, 10 is in parallel with the battery section 12. Under abnormal conditions the battery circuit includes additional battery sections 14, 16, an ampere-hour meter 40, counter e.m.f. cells 28 and a variable resistance 27 in parallel, and other contacts of the end-cell switch 31. After restoration of the source 1 . . 3 additional reotifiers 7, 8 are connected in parallel with the rectifiers 4, 5. The voltage relay 18 makes contact at 20 or 21 under low or high voltage conditions respectively. The first position operates through relays 61, 62, 68 to shortcircuit resistance 22 and increase the charge' rate, this condition being maintained so long as relays 67 or 93 are not energized. On high volts relays 71 and 67 operate and relays 62, 68 are released. When the source 1, 2, 3 fails relay 42 releases to operate relay 46. Thus the end cell switch 31 is lifted and latched at 30A, relays 78, 84 are operated and also relays 92, 93. The last transfer control by the voltage relay 18 and relays 61, 71 to the reversible motor 23. The end-cell switch connects in the battery sections 14, 16 and the counter e.m.f. cells 27. Relay 84 connects the resistances 27 in parallel with the cells 28. Relays 78, 84 remain energized until relay 82 is operated. Relay 78 also energizes relay 86 to prepare the circuits of relays 102, 104 so that the voltage relay contacts 20, 21 will respectively operate relays 104, 102 through the relays 61, 71. Relay 104 operates relays 44, 109 to connect battery 112 to drive the motor 23 in a direction to reduce the resistance in parallel with the cells 28. Relay 102 operates relay 44 only and connects the motor for reverse running. Release of relay 93 which occurs after restoration of supply operates relay 44 and ensures that all resistance 27 is in parallel with the cells 28. The motion of the motor is limited by switches 113, 114. Relays 92, 93 remain operated by reason of the relay 43 so long as the battery charge as registered by the ampere-hour meter 40 is incomplete so that the voltage relay 18 controls the compensating means until full charge is reached. When the source 1, 2, 3 is restored relay 46 releases, relay 121 is operated through contacts on relays 92 and 101 to operate relay 6 and connect in rectifiers 7, 8. The relay 101, like the relays 92, 93, is energized by the released relay 43 and consequently only de-energized when the contact 41 of the ampere-hour meter operates the relay 43 on a fully charged battery. Thus the normal control is restored to the voltage relay 18 and the rectifiers 7, 8 are disconnected. At the same time the end-cell switch is released by coil 30 and the battery connections restored to normal. A relay 115 is operated by relay 101 when the battery is not fully charged and closes the circuit of the relay 82. Since, however, this is in shunt with the limit switch 114 of the motor 23 the voltage compensation circuits remain closed until all resistance 27 is in parallel with the cells 28.